chore: add Node 12 and Node 14 to CI (#5821)

.travis.yml

@@ -38,6 +38,24 @@ jobs:
         - travis_retry npm run unit-with-coverage
         - npm run assert-unit-coverage
 
+    - node_js: "12.16.3"
+      name: 'Unit tests [Node 12]: Linux/Chromium'
+      env:
+        - CHROMIUM=true
+      before_install:
+        - PUPPETEER_PRODUCT=firefox npm install
+      script:
+        - travis_retry npm run unit
+
+    - node_js: "14.2.0"
+      name: 'Unit tests [Node 14]: Linux/Chromium'
+      env:
+        - CHROMIUM=true
+      before_install:
+        - PUPPETEER_PRODUCT=firefox npm install
+      script:
+        - travis_retry npm run unit
+
     # This bot runs all the extra checks that aren't the main Puppeteer unit tests
     - node_js: "10.19.0"
       name: 'Extra tests: Linux/Chromium'